<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>

    <style>
        div{
            width: 100px;
            height: 100px;
            border: 1px solid red;
            /*display: inline-block;*/
        }
        span{
            width: 100px;
            height: 100px;
            border: 1px solid red;
            display: inline-block;
        }
    </style>
</head>
<body>
  <div>div块元素</div>
  <span>span行内元素</span>
</body>
</html>